
struct Student {
    int carnum;
    char lendbook[10];
};


struct Book {
    int booknum;
    char bookname[20];
    float price;
    char bookcreat[20];
    int turefalse; 
};

struct Car {
    int carnum;
    char sex[5];
    char studentname[20];
    int studentclass;
};

extern  struct Book book[1000];
extern  struct Car car[1000];
extern  struct Student student[1000];